Metal surface treatment liquid

Abstract

The present invention provides a surface treatment liquid that can form an organic film sufficiently excellent in adhesive properties between metal and resin and is also excellent in chemical resistance properties, the surface treatment liquid being excellent in storage stability. The present invention relates to a metal surface treatment liquid for forming an organic film on a metal surface, wherein the surface treatment liquid contains a silane coupling agent and an acid and has a pH of 1.9 or less.

What is claimed is: 
     
         1 . A metal surface treatment liquid for forming an organic film on a metal surface, wherein the metal surface treatment liquid contains a silane coupling agent and an acid and has a pH of 1.9 or less. 
     
     
         2 . The metal surface treatment liquid according to  claim 1 , wherein the acid includes an acid having an acid dissociation constant of 4.8 or less. 
     
     
         3 . The metal surface treatment liquid according to  claim 2 , wherein the surface treatment liquid contains 0.010 to 10.0 mol/L of an acid having the acid dissociation constant. 
     
     
         4 . The metal surface treatment liquid according to  claim 2 , wherein the acid having the acid dissociation constant is selected from sulfonic acids and sulfuric acid. 
     
     
         5 . The metal surface treatment liquid according to  claim 1 , wherein the surface treatment liquid contains the silane coupling agent at 0.001 to 1.000 mol/L. 
     
     
         6 . The metal surface treatment liquid according to  claim 1 , wherein the organic film has a protrusion protruding to a side opposite to the metal. 
     
     
         7 . The metal surface treatment liquid according to  claim 6 , wherein the protrusion has a porous shape while protruding to the side opposite to the metal. 
     
     
         8 . The surface treatment liquid according to  claim 6 , wherein the protrusion has a protrusion length of 20 to 5000 nm. 
     
     
         9 . The surface treatment liquid according to  claim 6 , wherein the protrusion has a protrusion ratio of 10 to 5000%. 
     
     
         10 . The surface treatment liquid according to  claim 6 , wherein the organic film has the protrusion at an occupancy ratio of 10 to 95% on the side opposite to the metal. 
     
     
         11 . The surface treatment liquid according to  claim 6 , wherein
 the organic film includes a flat portion and the protrusion, and   the flat portion and the protrusion contain a silane coupling agent, and the protrusion is formed of an aggregate containing the silane coupling agent.   
     
     
         12 . The surface treatment liquid according to  claim 11 , wherein the flat portion of the organic film has a thickness of 10 to 300 nm. 
     
     
         13 . The metal surface treatment liquid according to  claim 1 , wherein a surface of the organic film has a surface roughness of 0.08 μm or more in Ra (arithmetic average roughness). 
     
     
         14 . The metal surface treatment liquid according to  claim 1 , wherein a surface of the organic film has a surface roughness of 0.70 μm or more in Rz (maximum height roughness). 
     
     
         15 . The surface treatment liquid according to  claim 1 , wherein a resin is disposed on the side opposite to the metal in the organic film. 
     
     
         16 . The surface treatment liquid according to  claim 1 , wherein the metal is copper or a copper alloy. 
     
     
         17 . The surface treatment liquid according to  claim 1 , wherein the metal is a metal circuit of a printed wiring board.